FEM: Keep result pipeline and only reload data. Fixes #20542

src/App/GroupExtension.pyi

@@ -61,6 +61,13 @@ class GroupExtension(DocumentObjectExtension):
         """
         ...
 
+    def getObjectsOfType(self, typename: str) -> List[Any]:
+        """
+        Returns all object in the group of given type
+        @param typename     The Freecad type identifier
+        """
+        ...
+
     def hasObject(self, obj: Any, recursive: bool = False) -> bool:
         """
         hasObject(obj, recursive=false)

src/App/GroupExtensionPyImp.cpp

@@ -278,6 +278,22 @@ PyObject* GroupExtensionPy::getObject(PyObject* args)
     }
 }
 
+PyObject* GroupExtensionPy::getObjectsOfType(PyObject* args)
+{
+    char* pcName;
+    if (!PyArg_ParseTuple(args, "s", &pcName)) {
+        return nullptr;
+    }
+
+    std::vector<DocumentObject*> objs = getGroupExtensionPtr()->getObjectsOfType(Base::Type::fromName(pcName));
+    Py::List result;
+    for (App::DocumentObject* obj : objs) {
+        result.append(Py::asObject(obj->getPyObject()));
+    }
+
+    return Py::new_reference_to(result);
+}
+
 PyObject* GroupExtensionPy::hasObject(PyObject* args)
 {
     PyObject* object;

src/Mod/Fem/feminout/importCcxFrdResults.py

@@ -66,21 +66,33 @@ def setupPipeline(doc, analysis, results_name, result_data):
     if not "BUILD_FEM_VTK" in FreeCAD.__cmake__:
         return
 
-    # create a results pipeline if not already existing
+    # create a results pipeline (dependend on user settings)
     pipeline_name = "Pipeline_" + results_name
-    pipeline_obj = doc.getObject(pipeline_name)
-    if pipeline_obj is None:
+    pipelines =  analysis.getObjectsOfType("Fem::FemPostPipeline")
+    fem_prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/General")
+    keep_results_on_rerun = fem_prefs.GetBool("KeepResultsOnReRun", False)
 
+    if not pipelines or keep_results_on_rerun:
+        # needs to create a new pipeline!
         pipeline_obj = ObjectsFem.makePostVtkResult(doc, result_data, results_name)
         pipeline_visibility = True
         if analysis:
             analysis.addObject(pipeline_obj)
     else:
+        # by default get the last one
+        pipeline_obj = pipelines[-1]
+        # maybe there is one with the correct name
+        named_pipeline = analysis.getObject(pipeline_name)
+        if named_pipeline:
+            pipeline_obj = named_pipeline
+
         if FreeCAD.GuiUp:
             # store pipeline visibility because pipeline_obj.load makes the
             # pipeline always visible
             pipeline_visibility = pipeline_obj.ViewObject.Visibility
 
+        # relabel the pipeline and load the data into it
+        pipeline_obj.Label = pipeline_name
         pipeline_obj.load(*result_data)
 
     # update the pipeline

src/Mod/Fem/femresult/resulttools.py

@@ -34,7 +34,7 @@ import FreeCAD
 from femtools.femutils import is_of_type
 
 
-def purge_results(analysis):
+def purge_result_objects(analysis):
     """Removes all result objects and result meshes from an analysis group.
 
     Parameters
@@ -43,11 +43,6 @@ def purge_results(analysis):
         analysis group as a container for all  objects needed for the analysis
     """
 
-    # if analysis type check is used, result mesh
-    # without result obj is created in the analysis
-    # we could run into trouble in one loop because
-    # we will delete objects and try to access them later
-
     # result object
     for m in analysis.Group:
         if m.isDerivedFrom("Fem::FemResultObject"):
@@ -68,6 +63,16 @@ def purge_results(analysis):
             analysis.Document.removeObject(m.Name)
     analysis.Document.recompute()
 
+
+def purge_postprocessing_objects(analysis):
+    """Removes all postprocessing objects and visualizations form the analysis
+
+    Parameters
+    ----------
+    analysis : Fem::FemAnalysis
+        analysis group as a container for all  objects needed for the analysis
+    """
+
     # result pipeline and filter
     for m in analysis.Group:
         if is_of_type(m, "Fem::FemPostPipeline"):
@@ -82,6 +87,24 @@ def purge_results(analysis):
     analysis.Document.recompute()
 
 
+def purge_results(analysis):
+    """Removes all result and postprocessing objects and result meshes from an analysis group.
+
+    Parameters
+    ----------
+    analysis : Fem::FemAnalysis
+        analysis group as a container for all  objects needed for the analysis
+    """
+
+    # if analysis type check is used, result mesh
+    # without result obj is created in the analysis
+    # we could run into trouble in one loop because
+    # we will delete objects and try to access them later
+
+    purge_result_objects(analysis)
+    purge_postprocessing_objects(analysis)
+
+
 def reset_mesh_deformation(resultobj):
     """Resets result mesh deformation.
 

src/Mod/Fem/femtools/ccxtools.py

@@ -162,7 +162,11 @@ class FemToolsCcx(QtCore.QRunnable, QtCore.QObject):
         self.fem_prefs = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/Mod/Fem/General")
         keep_results_on_rerun = self.fem_prefs.GetBool("KeepResultsOnReRun", False)
         if not keep_results_on_rerun:
-            self.purge_results()
+            # we remove the result objects only, not the postprocessing ones.
+            # Reason: "Not keep results" means for the user override the data. For postprocessing
+            #         this means keeping all filters, just change the data.
+            from femresult.resulttools import  purge_result_objects as purge
+            purge(self.analysis)
 
     def reset_all(self):
         """Reset mesh color, deformation and removes all result objects"""